"Haki?" Zoro looked at him with confusion.
"Haki is a power system that I don't understand completely. I do know about them but I don't know how to train them except one but even that might take one year to master."
"With Haki, you can attack any devil fruit user. You know about Gold Roger, right? Do you know about Vice-Admiral Garp, the hero of marines?" Zack asked.
As soon as he asked, Luffy shuddered as the sweat covered his body.
"Huh Luffy, what happened?" Zoro looked at him and asked.
"N-n-nothing!" Luffy shook his head and hands.
"I know about them. So, what's the point?" Nami asked curiously.
"Well, there are pirates who have the devil fruit that can destroy the world, devil fruit that can suck your soul, and devil fruit that can turn you into a dragon. These three devil fruits are in the hands of the strongest people in the world."
"But, during their prime, Vice Admiral Garp and Gold Roger were stronger than them despite not having the devil fruit powers. That's the power of Haki. Do you understand now?" Zack asked.
Hearing his words, three of them looked at him with wide eyes.
"Zoro, you set out to become the World's Strongest Swordsman, right?" Zack asked.
Zoro nodded his head and narrowed his eyes.
"The current World's Strongest Swordsman can fight these people. I don't know if he will lose or not but he can definitely fight these people. I don't want to discourage you but currently, the difference between you and him is this much."
Saying so, he put one hand on the boat and another hand almost above his head. When Zoro saw that, his eyes widened.
"Impossible! There can't be such a huge gap." Zoro shouted.
Zack clapped his hands and said "You know nothing about Haki. While Devil Fruits can also improve your strength, Haki takes them to a whole new level. If you want an example, then think of your full strength as a Haki user and Nami's strength as a person without Haki."
"Of course, I didn't mean you shouldn't fight him. In fact, I want you to fight him. Only then you will learn the difference between you and him. But…"
"But?" Zoro looked at him and asked.
"He might simply kill you." Zack took a deep breath and answered.
When Luffy and Nami heard those words, their eyes widened. Luffy still kept his serious expression but Nami freaked out.
"You don't plan to fight him now, do you?"
Zoro closed his eyes for a moment as he didn't reply. But, eventually, he opened his eyes and said "I set out in the seas to achieve my dream. If I die, then it is my fault. I will still fight him. I want to see just how much difference we have."
Zack's serious face slowly turned smiley. He laughed.
"Hahahaha! I knew you would say that. Damn, you are badass."
"Don't praise him! He is giving away his life." Nami turned her head at him and shouted.
"Relax! Didn't our captain say you this before? If you want to deal with the pirates, you must have your heart ready to die at any moment. Whether it is being a pirate or dealing with a pirate, you aren't ready to accept your death, you can never win against them." Zack looked at her with a serious expression and spoke.
Thud!
Nami fell to her knees and turned silent.
Everyone looked at her but nobody spoke until Zack finally opened his mouth.
"But, it doesn't mean you would die. I mean with a captain like him and swordsman like him, I think we can survive at least in the East Blue, nobody can defeat them except one person, and that person is actually a marine."
Nami raised her head and asked "You know a lot. Who were you before?"
Zack smiled and said "I told you I am the resourceful guy. I have gathered a lot of information including the Pirate Hunter Zoro and Monkey D. Luffy."
"How much do you know about us?" Zoro looked at him and asked. He was very curious because he had the feeling that Zack has a lot of knowledge.
"I know a lot but it also means how much information I can get from you. For example, I know your goal is to defeat the World's Strongest Swordsman but I have no idea bout your parents exactly."
"On another hand, I know about our captain's family but I don't know much about his family except their names and how strong they are." Zack answered.
Zoro and Nami suspiciously looked at Luffy while he turned around and whistled. They didn't pry too much so they shifted their attention toward Zack, especially Nami. Her heartbeat was really high at this moment.
"By the way, I forgot to mention about Zoan Type Devil Fruits. Unlike the other two, Zoan users inherit the brute strength that can even rival yours without any training at all. And, they also inherit the ability to transform into animals."
"Of course, there is also three classifications in Zoan Type. Normal, Ancient, and Mythical. Normal Zoan users are easy to find. Ancient Zoan users are rare and have the power of Ancient animals that used to live in our world."
"As for Mythical, as the name suggests, they are completely mythical with the power of mythical animals like I previously mentioned Dragon. Of course, there aren't many devil fruit users in the East Blue but in the Grand Line, the devil fruit users are crawling everywhere." Zack explained and finally shut his mouth.
"Hooo! I can't wait to fight all of them. What do you think, Zoro?" Luffy excitedly raised his hands and got filled with even more enthusiasm.
"It's going to be fun." Zoro also smiled.
"There is no fun about that." Nami looked at them and screamed. But, she quickly turned around and looked at Zack. She was expecting him to reveal her background but he didn't even speak a word.
Of course, she doesn't believe that he doesn't know anything especially after knowing all this. That's why she was confused. She made up her mind to ask him later.
But, she still had another question in her head.
"Zack, you are very weak and also young. How do you know so much stuff?"
Her eyes were full of suspicions. Even Zoro and Luffy were curious about it.
Zack brightly smiled and asked, "Do you know Big News Morgan?"
"Who?" Nami asked.
"The newspaper you read and all those birds who deliver them are controlled by him. In fact, he is the one who acknowledged Gold Roger as Pirate King." Zack mysteriously spoke.
"What?" Three of them had the same reaction as they looked at him.
Zack rolled his eyes and said "Why do you think people started calling him King of the Pirates? Is it because there was a title like that got acknowledged before? No! It was Morgan who acknowledged him that title after he obtained One Piece."
"Before coming to East Blue, I worked for him. It was quite a happy life. The news comes to us and we just fix it and print it in the newspaper. Of course, our news was completely manipulated by World Government. Whatever they want, we had to publish and something they don't want, we had to remove."
"Morgan wasn't a person who would let anyone hide the thrilling news. I began to realize that if he continues like this, the government might attack us. As you already know, I am really weak."
"So, I quitted the job and with his help, I came to the weakest sea in the world, East Blue. But, I still wanted to go on adventures. I wanted to train and get stronger."
"So, what better way than joining the person who is already at the top of the East Blue. I would get enough time to train while having fun adventures. So, I joined Luffy."
Zack had already made a completely fake story in his mind as soon as he joined Straw Hat. As a person who knows the future events, he can't just keep his mouth quiet many times.
So, instead of trying to act mysterious, why not give them a background that they will never know.
"No wonder, you know so much. You were actually working for such a big organization. But, is it really true, Zack? Government really changes the information we receive?" Nami asked.
Zack nodded his head and said "Don't you know Gold Roger's name isn't Gold Roger. It's Gol. D Roger. I don't know much about D but I heard the rumors that they are the enemies of Gods. Of course, in the literal sense, I mean World Government."
"Then Luffy?" Nami and Zoro pointed at him with confusion.
Zack smiled and shrugged his shoulders "As I said, it was just a rumor. There are no Gods in this world currently. Although Captain is special."
"Special Idiot!" Nami and Zoro replied at the same.